1. Field of the Invention
The present invention relates to equipment for taking electrical measurements of electrical circuits, components and/or devices and, more particularly, to electrical test leads for use with electrical test equipment for taking electrical measurements of electrical circuits, components and/or devices, such as digital multi-meters.
2. Background Information
Digital multi-meters (DMMs) and other types of electrical testing equipment are used to take various electrical measurements of electrical circuits, devices and/or components. Such electrical testing equipment may include one or more test leads that may be used in conjunction with the electrical testing equipment or not. The test leads may be used for various types of electrical measurement/testing. For instance, test engineers and/or technicians use DMMs for measuring voltages and currents in electrical circuits, control panels and/or electrical elements and/or components. Electrical test leads are used in conjunction with DMMs in order to manually connect the electrical subject (i.e. the electrical circuit, control panel, electrical element or component) with the DMM in order to obtain the electrical measurement. Such electrical test leads comprise wires having a plug on one end for receipt by the DMM and a probe, clip or connector on the other end for contact with the electrical test subject.
DMMs are internally fused in order to protect their internal circuitry from harm during test measurement. Typically, DMMs are internally fused at ten amps (10 A) for circuit current measuring. Measuring circuit current requires the test leads to be inserted into different test lead reception terminals of the DMM versus those used for measuring voltage. Occasionally, however, engineers/technicians forget to switch the test leads from the current measuring test lead reception terminals of the DMM to the voltage measuring test lead reception terminals of the DMM. If the test leads are in the current measuring test lead reception terminals of the DMM and the test leads are used to take a voltage reading (measurement), a short circuit condition will occur, causing fuses to blow. Since electrical component(s) are commonly protected via fuse or circuit breaker at amperages less than the DMM, the electrical component will lose power by blowing its fuse or tripping its circuit breaker, thus causing the electrical component(s) or electrical system to fail.
Also, even if the electrical components are fused greater than the DMM, a short circuit condition will cause the internal fuse of the DMM to blow thus requiring the DMM fuse to be replaced. While replacing the fuse on a DMM is not a difficult task, it is time-consuming. Moreover, DMM fuses are an atypical type of fuse which is expensive compared to ordinary glass/ceramic fuses as used in typical industrial electrical applications and the like. As such, DMM fuses are not likely to be stored on the shelf in a company's spare parts depot.
Another manner in which electrical test leads are typically used by engineers and/or technicians is as jumpers between positive voltage terminals and other terminals in order to test an electrical control system's inputs and outputs during startup or when checking out a control panel. However, accidental touching of a neutral or control panel ground will cause a short circuit with the negative results as indicated above.
It is therefore evident from the above that there is a need for a manner of protecting electrical components when using test leads for various typical and atypical uses and/or applications.